The present invention, in some embodiments thereof, relates to image processing and, more particularly, but not exclusively, to image processing based on photometric stereo.
Photometric stereo (PS) has been a powerful tool used for three-dimensional (3D) object acquisition techniques. Conventional PS methods estimate surface orientation by analyzing how a surface reflects light incident from multiple directions. Known PS methods are disclosed in S. Barsky and M. Petrou, Pattern Analysis and Machine Intelligence, IEEE Transactions on, 2003, 25(10):1239-1252; R. Mecca and J. D. Durou, 2011, In Image Analysis and Processing—ICIAP 2011—16th International Conference, Ravenna, Italy, pages 286-295; and R. Onn and A. M. Bruckstein, 1990, International Journal of Computer Vision, 5(1):105-113.
Traditionally, PS employs a two step process, wherein in a first step the direction of the normal vector to the surface is computed for the entire surface, and in a second step, the computed direction is used for calculating of the height of the surface.